With the mass growth of the Internet there has occurred a rising flood of unwanted messages. Many of these messages are what are typically referred to as “spam”. Spam is the electronic equivalent of junk mail. In addition to junk mail, other messages may include programs such as viruses or worms. One of the intents of a worm is to control a host computer for the purpose of sending more spam. Spam consumes a large amount of network resources as well as wasted time for the users having to deal with it.
There have been many solutions developed to deal with spam and unwanted messages. The most common being the use of filtration software. Filtration software examines the content of a message and determines if the message is wanted or not. Typically filtration software maintains a database of sites known for sending unwanted messages as well as databases of keywords that help to identify an unwanted message. Such a scheme is costly in the use of computer time, as it must scan every message for content and check with a database. Further, it is simple to avoid filtration software by changing the address of the sender and modifying the words of the message. Finally, filtration software may exclude wanted messages based upon what is falsely considered a valid keyword or address match.
An advancement in filtration software is to use Bayesian or heuristic filters to statistically identify unwanted messages based on the frequencies of patterns in the message. These types of filters are weak when dealing with shorter messages, as they do not have enough data to make an intelligent decision.
Another alternative is to create lists of IP addresses that are known to be used by senders of unwanted messages. These are known as “blacklists” and aid in blocking messages from the listed addresses. The problem with this approach is that the blacklisted senders move addresses readily and the person who is reassigned the previous address may still be on the list, thus being incorrectly identified as a spammer.
Thus, there is a need for a means of detecting unwanted messages in a cost effective and efficient manner. The present invention addresses this need.